Fluorinated cationic compounds such as perfluoroalkyl quaternary ammonium derivatives are known in art, which have a saturated perfluoroalkyl terminal chain. For example, fluorinated cationic compounds disclosed in U.S. Pat. No. 4,836,958 contain such a perfluoroalkyl terminal chain group having up to 18 carbon atoms. In “Molecular Aggregation Structure and Surface Properties of Poly(fluoroalkylacrylate) Thin Films” Macromolecules (2005), 38(13), 5699-5705, Honda et al. describe that a perfluoroalkyl chain of at least 8 carbons is necessary for the individual perfluoroalkyl chains to be maintained in a parallel orientation. For such perfluoroalkyl chains containing fewer than 8 continuous perfluorinated carbons, a reorientation occurs, which decreases or even eliminates the performance of the materials in exhibiting desirable surface properties. Commercially available fluorinated pyridinium cationic surfactants usually contain a saturated perfluoroalkyl terminal chain of at least 8 or more carbons.
The high price of fluorinated surfactants is determined by the amount of fluorine incorporated therein. A higher fluorine content results in a higher price. Therefore, it is desirable to provide fluorinated surfactants having shorter fluorinated chains or less fluorine substitution in the chain while still providing equivalent or even better surface properties compared to those fluorinated surfactants which contain longer fully fluorinated perfluorinated chains.
It has been discovered in this invention that a fluorinated pyridinium cationic surfactant having a short partially fluorinated terminal chain provides desirable surface effects in a variety of applications, and is particularly useful in oil field and gas field applications.